Mandatory iodine fortification

Most bread is set to become iodine fortified over the next 18 months in a bid to combat New Zealanders' growing problem of iodine deficiency.

"For some years, the amount of iodine people are consuming has been dropping. Reasons include New Zealand's naturally low soil iodine levels; reductions in the use of iodised salt as sea and rock salts have become more popular; a general reduction in the amount of salt consumed; and the move away from the use of iodine-based disinfectants in industry and the home. The last Total Diet Survey highlighted the problem, with the levels New Zealanders now far lower than those of people in other nations", explains Jenny Reid, New Zealand Food Safety Authority (NZFSA) Assistant Director (Joint Food Standards).

"Iodine levels that are too low irreversibly impair the development of intelligence in children, beginning in the womb and continuing through childhood. Low iodine levels in adults are also a concern, with severe cases leading to goitre."

Food Standards Australia New Zealand has decided to make it mandatory for bread manufacturers to replace non-iodised salt in breads with iodised salt. Organic products and unleavened bread (such as pita and tortilla) is exempt.

Internationally the preferred option for increasing iodine levels in food is to ensure all salt (including salt used in processed foods) is iodised, as it is a simple and low cost way of increasing the iodine content of a range of foods.

Iodine is an essential nutrient for humans and iodine deficiency has been linked to a host of problems. Although iodine is only needed in very small amounts, it is vital for thyroid hormones to maintain the body's metabolic state and to support normal growth and development in children.

As iodine is essential for normal brain development, it is particularly important that unborn babies and young children have adequate intakes. Severe cases of iodine deficiency can lead to stunted growth and mental retardation in children. A number of studies have also reported adverse effects on hearing as well as motor and cognitive function in children associated with moderate and severe iodine deficiency. Another serious condition related to iodine deficiency is goitre, which causes the thyroid gland in the neck to become enlarged which increases the risk of thyroid diseases in later life.

Even when eating a balanced diet it can be difficult to get enough iodine in New Zealand, as vegetables, fruits and grains grown domestically have very low levels of iodine compared with food produced in other parts of the world. To ensure a higher intake of iodine people can choose foods that are naturally rich in iodine, such as seafood (fish, shellfish and seaweed), milk and milk products, seameal custard and eggs.

Another source of iodine is iodised table salt. The Ministry of Health recommends limiting overall salt intake to reduce the risk of stroke and heart disease, however, it advises that if salt is used for cooking and at the table it should be iodised.

Bread manufacturers have until September 2009 to comply with the new regulation to allow time to make the required changes to manufacturing and labelling. It will also give the salt industry time to increase the production of iodised salt.

There is more information about iodine on NZFSA's website at: www.nzfsa.govt.nz/consumers/chemicals-toxins-additives/iodine/index.htm .